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  1. Audioguru

    Charging Issue

    Maybe you are trying to charge the big battery with a little solar panel on a cloudy day? The output from the battery (at noon in the Sahara Desert (on the equator of earth) on a sunny day?) is only about 3.2A. The car power supply for the drone needs an input of 9A. So if the solar thing is...
  2. Audioguru

    HOW TO ID-- A 12 VOLT ZENER DIODE --ONE WATT --

    I found a battery charger circuit on the internet that has good voltage and current regulation. It had horrible errors that I corrected:
  3. Audioguru

    Power adapter voltage drop/load

    Voltage matching is very important but you do not need to match current. The starter motor in a car in winter draws 400A or more but the clock that is powered from the same battery uses only 0.01A. Get a power supply that provides the correct voltage and can supply the current that is needed or...
  4. Audioguru

    Noob needs help building a circuit board

    The Moderator edited my post. I always say that ads rate speakers and amplifiers with phoney Whats instead of real Watts. I said, "Many speakers are rated at 50 Whats". I bought a little name brand amplified speaker system that was on sale and when I saw the ad say 150W then I knew it was 150...
  5. Audioguru

    HOW TO ID-- A 12 VOLT ZENER DIODE --ONE WATT --

    A battery charger must provide the correct voltage and the correct current. The horrible circuit did not provide the correct voltage. A bridge rectifier does not limit the current so the battery might boil all its electrolyte away then its plates might get warped. The 15V from the transformer is...
  6. Audioguru

    Reduce amperage without reducing voltage. Diodes? [Noob]

    I have many LEDs that look like ordinary LEDs but they have 3 colors and a microprocessor inside that lights the colors in many sequences. They do not need a resistor because it is inside. I am posting the datasheet of an ordinary red LED for you to see its maximum allowed current, and how to...
  7. Audioguru

    Lm386 Audio amplifier

    Didn't you look at the manufacturer's datasheet of the LM386 amplifier? With a brand new 9V battery its output is shown on a graph to be 6V peak-to-peak into 8 ohms which is 2.122V RMS so the output power is (2.122V squared)/8 ohms= 0.56W that is not very loud. Our hearing's sensitivity is...
  8. Audioguru

    How to create a magnetizer

    The project has nothing to do with magnetism. It simply makes a high voltage, very high current pulse.
  9. Audioguru

    Meaning of switched jack socket pins

    Your schematic has parts of the jack all over the place. Maybe this explains how it works:
  10. Audioguru

    My OPA695 amplifier's voltage

    R8 and R9 are connected together on the schematic but since you measure different voltages on them then they are not connected together in your circuit.
  11. Audioguru

    How to get a constant 5V output regardless of input voltage?

    Your two CR2450 cells in series produce about 6.4V when new and about 4.8V when run down. The datasheet of a 7805 voltage regulator says its minimum input is 7V so you cannot use it. A "low dropout" 5V regulator minimum input voltage is about 5.2V.
  12. Audioguru

    HOW TO ID-- A 12 VOLT ZENER DIODE --ONE WATT --

    I think you are using a circuit from a 3rd world country designed by someone who knows little about electronics. You did not see the photo I posted of the TIP122 pins. The middle leg is the collector but the schematic of the circuit shows the zener diode connected to the base, not the collector...
  13. Audioguru

    Building an adapter - dual quarter-inch and 3.5 mm, to 3.5 mm

    Your wiring might blow up the amplifiers if the pc and the audio interface are both connected together. Added resistors will ruin the sound. Volume controls and a mixer are never connect to the output of an amplifier, they are always at the input.
  14. Audioguru

    Power adapter voltage drop/load

    A power supply with a low maximum output current is usually cheap and has such a high resistance that its voltage drops a lot when it has its rated load. So they simply make it with a higher voltage (when it has no load) so that its voltage is correct at its rated current. A high current power...
  15. Audioguru

    Noob needs help building a circuit board

    Many speakers are rated at 50 Watts. You need to know what is the real maximum power rating. If an amplifier is powered by 5V USB and is perfect and produces an output with no voltage loss then its voltage swing is 5V peak to peak. But the amplifier is not perfect and might produce only 3V...
  16. Audioguru

    Dead Lithium Ion Batteries

    A Li-Po is a Lithium-ion battery in a plastic case. A cell's voltage is 3.0V or 3.2V when dead to 4.2V when fully charged. Yours at 1.6V to 2.4V were discharged too low and are badly damaged. I last used Ni-Cad batteries about 20 or 30 years ago and every one of them ended up shorted. Ni-MH has...
  17. Audioguru

    Power adapter voltage drop/load

    The ICL7660 and LT1054 are not voltage regulators. Instead they are voltage converters to produce a negative voltage from a positive voltage. Their voltage regulation is not good.
  18. Audioguru

    HOW TO ID-- A 12 VOLT ZENER DIODE --ONE WATT --

    You connected the base and collector pins of the TIP122 backwards so that it is not a darlington transistor anymore. That is why the zener diode burns out. I showed a photo of the labelled pins as shown in its datasheet. The big black diode you added does nothing since it is not a 12V zener...
  19. Audioguru

    Dead Lithium Ion Batteries

    Lithium is extremely reactive and if charged or discharged wrong it can explode or catch on fire. A lithium-ion or Li-Po cell that has been discharged to below 3V is dangerous because the ions have converted to lithium metal that shorts the cells and causes an explosion or fire if it is charged...
  20. Audioguru

    Noob needs help building a circuit board

    If the computer speakers have a Name Brand then info about them is everywhere. But if they are cheap ebay junk then good-luck. On the web you search for the owner's manual of the computer speakers and the manual will say the voltage of the power supply (or USB 5V power). The power supply for the...
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